525 efi performance?
 

Hello, I am new to high performance boats, I have just recently entered the game 3 months ago and have a twin staggered 525 efi engines on my Fountain. I was wondering if I could get some pointers from you guys since I see there is a lot of experienced people on here.

When running my boat the max rpms she hits is 4000-4500. I know that these engines in stock should hit 5400 rpms. Also my props size is big and I was told that its best to have smaller props. I was wondering is that the only reason or could there be something else?

Also what upgrades do you guys recommend? Note that I looking for something that is fairly safe on the engines and wouldnt cause any break downs. At the end of the day I want to take the boat out and enjoy my weekend!

Thanks any advise would be appreciated..

Welcome to the boards. I'm sure some of the experts will chime in soon. But to help you, you need more info. What year and size is your boat? What size props are on there now? How many blades on the props? How is the hole shot now with this setup? If it is real hard to get out of the hole and you only get the tachs to 4500, then I would say you need to go down at least 5 inches in pitch. But I find that hard to believe someone would sell a boat so over propped. You could have something else going on. Lets see what someone else comes up with.

Gary thanks.

My boat is a 2006 Fountain Lightning, and the current props are 30'5 blade maximus props.

I dont understand what you mean when you say "How is the hole shot now with this setup? If it is real hard to get out of the hole and you only get the tachs to 4500, then I would say you need to go down at least 5 inches in pitch."

bear with me as I said I am kinda new to powerboats.

Thank again.

In 2006, Fountain made 42 Lightnings and 35 Lightnings...which one do you have?

Based on what I know from my 3rd party company and broker when purchasing the boat its a 2006, 38ft.

Fountain had a 38 lightning in 06. I see lots for sale.

Try the trim button.

thats after trimming, then the engines start heating up so I take it easy on the trim...

Your temp rises when you trim up? Sounds like you may have other issues.

You should be propping for around 5200 RPMs. Sometimes when somebody sells a boat, they throw on some props that they had laying around rather than the set that should really be on the boat.

Maximus props act like a larger prop than say a bravo. I'm on the rev limiter with a 28 Bravo, and I only see around 5000 w/ a 26 Maximus.

There could be some issues, but I see the temp raising after trimming for a while. Usually where I am from powerboat owners upgrade their cooling systems since it gets really hot over here, with outside temp hitting 122 degrees...

I have been advised to go with a 28’ 4 blade props, but would that give me more rpms?

I have a 42 fountain 2006 with staggered 525 with 32p 4 blade bravo she will hit 80 at 5200 rpm with trim at 5 on the gage. no problems with overheating. Are you getting good water pressure ?

what about the 38 !!!???

You're new to high performance boats and have a Fountain with twin 525's? Take Tres Martin's course!

A 38 Lightning with 525's should come with 32 pitch 4 blade Bravo 1's. The boat should run around 90 at 5250 rpm.

Sounds to me like you may need transom mount raw water pick ups but i would be surprised if it did not have them already.. The 5 is a lot of prop for that set up i would think a 28 or 30 B1 but thats just a guess on my part, and yes the 28 will bring up the rpm

How many hrs are on he motors?? The first thing you lose is RPM when the motor is getting weak. Might what to check that.

Props are too big, especially with the extreme high air temps you have. High ambient temps cause a loss of HP.
If you switched to 27" Maximus props or 30" Bravo 4 blades you would see about 5100rpms.

i can see it already,,his next comment is going to be that his props blow out after switching to 28 bravos....lol

+1

120 degree ambient temp will hurt power a lot, surely it should call for at least one pitch less than normal

Thanx Keytime looks good!!

thanx Glassdave, I will have smaller props installed over the weekend and c how it runs!

Currently motos have 220hrs.

What should be done do repower the motors? rebuild?

thnxx

Thanx Griff, I will be changing the props over the weekend and c how it runs then.

Just the top ends. They seem to need refreshening around 220-250 hours.

top ends?

Valve jobs. valve springs, head gaskets, etc. are a good idea to have done around 300hrs on 525EFI's

Also, you should pressure test the headers. If/when they leak, they can cause a major engine failure.